HCG levels?

On March 21st I was supposed to be 9 weeks and started bleeding. Ultrasound confirmed blighted ovum and my HCG levels were 20,000. A week later I started bleeding very heavily. Passed the sac and my levels were a little under 10,000. I bled until my d&c on April 8th.

To people who had similar experiences. How long did it take for you to get a negative pregnancy test?

I'm asking because I've gotten 3 faint positives these past 2 days and I don't know if I should be excited or not..